Ethernet traffic is sent across G.SHDSL interfaces in dual-pair mode (M-pair mode where M=2). The term G.SHDSL refers to selectable one/two-pair high speed digital subscriber lines (SHDSL) that conform to ITU-T recommendation G.991-2. The Ethernet frames are sent and received on the Ethernet port on a central SHDSL transceiver unit (STU-C) and on a remote SHDSL transceiver unit (STU-R).
Typically, Ethernet frames received at the STU-C and the STU-R are converted to a High-Level Data Link Control (HDLC) format, which is inserted into a DS0 based pulse-code modulated (PCM) stream. This stream is distributed between the DSL pairs in a sequential manner. For example, timeslot 1 is inserted in timeslot 1 of DSL pair 1 and timeslot 2 is inserted in timeslot 1 DSL pair 2, and so on. Thus, if a line in pair 1 or pair 2 fails, the Ethernet connection is lost, because the half of the data is sent over the broken line and is not received at the STU-R.
There is a need in the art for a method and system to send Ethernet frames over a pair of digital subscriber lines even when one of the lines in the pair of digital subscriber lines is faulty and/or broken.